Non-lens-based surgical techniques for presbyopia correction.

Presbyopia is the most prevalent refractive error. With a progressive aging population, its surgical correction is an important challenge for the ophthalmology community, as well as the millions of patients who suffer from it, and who are increasingly demanding alternatives to its correction with glasses or contact lenses. A review is presented with a synthesised discussion on the pathophysiological theories of presbyopia and an updated and analytical description of the non-lens involvement surgical techniques used to treat presbyopia. Corneal procedures include various types of corneal implants and photo-ablative techniques that generate a multifocal cornea, or monovision. Scleral procedures exert a traction on supralenticular sclera that supposedly would improve the amplitude of accommodation. None of the techniques are able to completely eliminate the need for near -vision glasses, but many of them manage to improve the refractive status of the patients. More studies with rigorous and standardised methods and longer follow-up are needed to evaluate the changes in the near vision of the patients, in order to corroborate the real and practical usefulness of many of these techniques.

Bilbao-Calabuig R ，Llovet-Osuna F 《-》

Intracorneal Inlays for the Correction of Presbyopia.

Binder PS 《-》

BCLA CLEAR Presbyopia: Management with corneal techniques.

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report reviews the evidence for the treatment profile, safety, and efficacy of the current range of corneal techniques for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. In presbyopia correction by conductive keratoplasty, radiofrequency energy is applied to the mid-peripheral corneal stroma, leading to mid-peripheral corneal shrinkage and central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Craig JP ，Barsam A ，Chen C ，Chukwuemeka O Jr ，Ghorbani-Mojarrad N ，Kretz F ，Michaud L ，Moore J ，Pelosini L ，Turnbull AMJ ，Vincent SJ ，Wang MTM ，Ziaei M ，Wolffsohn JS ... -  《-》

Revisiting monovision for presbyopia.

Mahrous A ，Ciralsky JB ，Lai EC 《-》

Presbyopia: Effectiveness of correction strategies.

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

Wolffsohn JS ，Davies LN 《-》